NEW YORK (AP) — Platinum and palladium slumped Friday as investors fretted about the prospects for growth in emerging markets.

Both metals, which are used to make catalytic converters for autos, tend to track the outlook for growth in emerging economies such as China and Latin America. A downturn in emerging markets began Thursday following signs that manufacturing was contracting in China, a major importer of raw materials and a key driver of global economic growth.